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Kinetics of molecular decomposition under irradiation of gold nanoparticles with nanosecond laser pulses—A 5-Bromouracil case study

Marques, Telma S., Schürmann, Robin, Ebel, Kenny, Heck, Christian, Śmiałek, Małgorzata A., Eden, Sam, Mason, Nigel, Bald, Ilko (2020) Kinetics of molecular decomposition under irradiation of gold nanoparticles with nanosecond laser pulses—A 5-Bromouracil case study. The Journal of Chemical Physics, 152 (12). ISSN 0021-9606. (doi:10.1063/1.5137898) (KAR id:81188)

Abstract

Laser illuminated gold nanoparticles (AuNPs) efficiently absorb light and heat up the surrounding medium, leading to versatile applications ranging from plasmonic catalysis to cancer photothermal therapy. Therefore, an in-depth understanding of the thermal, optical, and electron induced reaction pathways is required. Here, the electrophilic DNA nucleobase analog 5-Bromouracil (BrU) has been used as a model compound to study its decomposition in the vicinity of AuNPs illuminated with intense ns laser pulses under various conditions. The plasmonic response of the AuNPs and the concentration of BrU and resulting photoproducts have been tracked by ultraviolet and visible (UV–Vis) spectroscopy as a function of the irradiation time. A kinetic model has been developed to determine the reaction rates of two parallel fragmentation pathways of BrU, and their dependency on laser fluence and adsorption on the AuNP have been evaluated. In addition, the size and the electric field enhancement of the decomposed AuNPs have been determined by atomic force microscopy and finite domain time difference calculations, respectively. A minor influence of the direct photoreaction and a strong effect of the heating of the AuNPs have been revealed. However, due to the size reduction of the irradiated AuNPs, a trade-off between laser fluence and plasmonic response of the AuNPs has been observed. Hence, the decomposition of the AuNPs might be limiting the achievable temperatures under irradiation with several laser pulses. These findings need to be considered for an efficient design of catalytic plasmonic systems.

Item Type: Article
DOI/Identification number: 10.1063/1.5137898
Subjects: Q Science
Divisions: Divisions > Division of Natural Sciences > Physics and Astronomy
Depositing User: Nigel Mason
Date Deposited: 12 May 2020 15:56 UTC
Last Modified: 09 Dec 2022 05:43 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/81188 (The current URI for this page, for reference purposes)

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